Two senior DEA officials explained that the reason parallel construction is used is to protect sources (such as undercover agents or informants) or methods in an investigation. One DEA official had told Reuters: "Parallel construction is a law enforcement technique we use every day. It's decades old, a bedrock concept."

An example from one official about how parallel construction tips work is being told by Special Operations Division that: "Be at a certain truck stop at a certain time and look for a certain vehicle." The tip would allow the DEA to alert state troopers and search a certain vehicle with drug-search dogs. Parallel construction allows the prosecution building the drug case to hide the source of where the information came from to protect confidential informants or undercover agents who may be involved with the illegal drug operation from endangering their lives.

A number of former federal agents had used parallel construction during their careers, according to Reuters interviews. Most of the former agents had defended the practice of parallel construction because no falsified evidence or illegally obtained material were presented in courts. A judge can rule evidentiary material inadmissible if it is suspected that the evidence was obtained illegally.

Parallel construction in this case in the US usually is the result of tips from the DEA's Special Operations Division that are derived from sources within foreign governments, intelligence agencies or court-authorized domestic phone recordings. According to a senior law enforcement official and a former US military intelligence official tips are not given to the DEA until citizenship is verified to avoid any illegal wiretapping of US citizens who are abroad. US authorities require a warrant to wiretap domestic US-persons (citizens and non-citizens alike) and to wiretap US citizens who are abroad.[1]

The Reuters piece occurred amid reporting of the 2013 NSA leaks, although it made no "explicit connection" to the Snowden leaks.[3][4]..